Transition Metal Allyls, V. The Preparation and Structure of [NiX(PmenthylR1R2)(η3-allyl)] Complexes

A number of adducts formed by reacting [NiX(η3-allyl)]2 complexes with optically active tert.- phosphines, in which optically active centres are found both at the phosphorus atom and in a substituent, have been isolated and their structures investigated in solution by NMR spectroscopy. The absolute configuration of the phosphine in [NiCl{Pm enthyl(Me)But}(η3-C3H5)] has been determ ined by X-ray crystallography. The relevance of the results to the nickel-catalyzed asymmetric codimerisation of alkenes is discussed.